Two-temperature refrigerator including moisture control means

ABSTRACT

A refrigerator including an upper freezer compartment, a lower fresh food compartment and an insulating defrost water receptacle positioned between the compartments for collecting defrost water formed by the melting of frost during defrosting of the freezing compartment. The receptacle includes a plastic drain means for transferring the water to the fresh food compartment and having an inlet formed of a plurality of perforations which are normally sealed by the frost and ice formed therein during normal refrigerating operation of the refrigerator.

United States Patent 1 i i i v [111 3,774,408 Pruehs Nov. 27, 1973 TWO-TEMPERATURE REFRIGERATOR INCLUDING MOISTURE CONTROL MEANS imary Examiner-william J. Wye 75 Inventor: Leslie L. Pruehs, Louisville, Ky. Rule [73] Assignee: General Electric Company,

Louisville, Ky. [57] ABSTRACT Filed! p 1972 A refrigerator including an upper freezer compart- [211 APPL No: 289,818 ment, a lower fresh food compartment and an insulating defrost water receptacle positioned between the compartments for collecting defrost water formed by l l Cl the melting of frost during defrosting of the freezing 6 62/291 compartment. The receptacle includes a plastic drain [51] Int. Cl. F25d 21/14 means for transferring the water to the fresh food [58] Field of Search 62/273, 285, 287, compartment and having an inlet formed of a plurality 137/62 of perforations which are normally sealed by the frost and ice formed therein during normal refrigerating op- [56] 1 References C ted eration of the refrigerator UNITED STATES PATENTS 3,696,632 10 1972 Carlin 62/285 2 Clams 3 figures )2. C L o '0 0 O r e t 19 u w L d 0 o l9. 7 H K f BACKGROUND OF THE INVENTION A well-known, two-temperature refrigerator described for example in U.S.Pat. Nos. 2,442,204-Jan'os; 2,595,874-Nanson; and 2,548,608-Janos, comprises an upper freezer compartment formed by a metal liner having refrigerant tubing on the exterior surface thereof, a lower fresh food compartment spaced from the freezer compartment and a heat-insulating, moisture-impervious drain pan or receptacle below and spaced from the freezer compartment liner for collecting water resulting from the melting of frost on the exterior of the freezer compartment liner and including means for conducting that water to the fresh food compartment during defrosting of the freezer compartment. 7

Since this drain means will also provide a passage for the flow of moist air between the fresh food compartment and the space'between the recpetacle and the freezer compartment, it is desirable that the passage be closed or substantially closed during normal refrigerating operation of the refrigerator. In the first two aforementioned patents, a drain tube is provided having its inlet communicating with the interior freezer compartment and its outlet in the fresh food compartment. The portion of the drain tube extending through the receptacle bottom wall is provided witha plurality of openings through which water can flow from the receptacle to the fresh food compartment during defrosting, these openings being normally closed by amaterial such as cellulose sponge which prevents the free circulation of air therethrough. In the Janos US. Pat. No. 2,548,608, the upper end of the drain passage is provided with an element that expands on freezing, thereby closing the I drain during normal refrigerating operation.

It is a general object of the present invention toprovide a low-cost defrost water pan or drain or receptacle including improved drain means adapted to be selfsealing, that is, adapted to be sealed by accumulated frost or ice during normal operationv of the refrigeration system.

SUMMARY OF THE PRESENT INVENTION In accordance with the present invention, there is provided a two-temperature refrigerator including an upper freezer compartment defined by a metal liner having refrigerant tubing engaging the exterior surface thereof, a lower fresh food compartment spaced from the freezer compartment and a water-collecting receptacle positioned below the freezer liner for collecting defrost water. dripping from that liner during defrosting thereof. The water-collecting receptacle is composed of moisture-imprevious, heat-insulating material providing an insulating barrier between the two compartments and includes a plastic drain means for conveying water from the receptacle to and through the fresh food liner top. The drain means comprises a discshaped portion having its periphery molded into the heat-insulating material and a tubular portion having a lower end extending through the top wall of the fresh food compartment. The area of the disc-shaped portion the freezer compartment is above freezing temperatures, but-which become sealed by the collection of ice and frost therein during normal operation of the refrigerator.

BRIEF DESCRIPTION OF THE DRAWING With reference to the accompanying drawing,

FIG. 1 is a sectional view of a portion of a refrigerator cabinet incorporating the present invention;

FIG. 2 is an enlarged sectional view of the drain means forming part of the present invention; and

FIG. 3 is a top plan view of the drain means illustrated in FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to FIG. l of the drawing, there is shown a refrigerator including outer walls, such as wall I, a metalliner 2 defining a freezer compartment 3 and a liner 4 defining a fresh food compartment 5 which is spaced from the freezer compartment 3. Substantially all of the space between the compartments and the outer walls of the refrigerator cabinet is filled with heat-insulating material 6. The freezer compartment 3 is maintained at below-freezing temperatures by an evaporator which includes a plurality of turns of tubing 7 secured to the exterior of the liner 2. The fresh food compartment is maintained at above-freezing temperatures by means of an evaporator 8. As is described in the aforementioned patents, this type of refrigerator is designed to provide automatic defrosting of the evaporator 8"during each off cycle, the freezer compartment being periodically manually defrosted bycompletley de-energizing the refrigeration system until the liner 2 reaches an above-freezing temperature .at which frost and ice collecting on both the interior and exterior surface thereof melts.

In normal use of a refrigerator of this type, defrosting of the freezer compartment is required only after the refrigerator has been operating for a number of months. During this time, moisture migrating into and through the cabinent insulation collects on the exterior surfaces of the freezer compartment and must be removed and disposed of during each defrost operation since the continuous accumulation of moisture and frost in the insulation would detract from the insulating value thereof. For the purpose of receiveing and disposing of this defrost water, there is provided a drain pan or receptacle positioned below the freezer compartment and spaced therefrom for collecting the defrost water dripping from the freezer compartment walls and drain means for conducting the defrost water from the receptacle into an accessible portion of the fresh food compartment where it can be collected in a suitable pan during defrosting.

In order to provide for the collection of water resulting from the melting of frost from the exterior of the liner 2 during the defrost operation and also to minimize heat flow between the compartments 3 and 5, there is'provided a combination heat barrier and defrost water receptacle 10 having a slanting bottom wall 11 which is spaced from the bottom wall 12 of the freezer compartment and defines therewith an insulating air space 14. The receptacle 10 is molded of a moisture-impervious, heat-insulating material such as a foamed polystyrene as, for example, by the molding of foamable polystyrene beads.

In accordance with the present invention, there is provided drain means for draining defrost water from the receptacle 10 during the periodic defrosting of the freezer compartment 3, which is self-sealing during normal operation of the refrigerator so as to prevent the migration of moisture from the fresh food compartment into the space 14 where it can collect on the exterior surfaces of the liner 2. The sealing of the drain also prevents the flow of air from the fresh food compartment into this space which can normally take place due to temperature or pressure differentials resulting, for example, from the opening and closing of the door (not shown) provided for closing the access opening to the fresh food compartment 5.

This drain means 16, shown in greater detail in FIGS.

' 2 and 30f the drawing, comprises a one-piece plastic member of polystyrene or other suitable plastic molded as an insert into the body of the receptacle 10 during the molding of the receptacle. The drain means 16 includes a disc-shaped portion 17, the outer edges 18 of which are anchored in the foamed resin forming the bottom wall 11. The central portion 19 of the discshaped portion 17 is provided with a plurality of holes or perforations 20, communicating with a tubular portion 21 of the drain means which extends through the top wall 22 of the fresh food liner 4.

Since both the receptacle l and the drain means 16 are composed of plastic material, they have a low thermal mass and rather closely follow the temperature of the air within the space 14. During defrosting of the freezer compartment 3, that is, when this compartment is brought to above-freezing temperatures, the air within the space 14 is also above-freezing temperatures and-the receptacle and the drain means are sufficiently warm so that defrost water dripping from the exterior surfaces of the liner 2 will readily flow through the passages 20 and into a suitable receptacle placed in the fresh food compartment below the tubular portion 21.

After the defrost operation and as soon as the freezer compartment 3 is brought down to below-freezing temperatures, any residual moisture within or in the vicinity of the drain passages 20 quickly freezes. Within a short period of time, moisture contained in the fresh food compartment migrating upwardly into the passages will collect as frost therein and this frost will grow to the point where all of the passages 20 are closed or sealed by the frost. Thus, the frost forms an air seal between the fresh food compartment and the air space 14 below the freezer compartment which prevents further migration of moisture from the fresh food compartment into that air space or the flow of fresh food air through the drain during subsequent operation of the refrigerator. During the next defrost operation sages are preferably of a relatively small diameter and of a length sufficient to provide an internal surface in each of the passages effective to accelerate the collection of defrost layers. Suitable passages orperforations 20 have a diameter of about 0.10 inch and a length of about 0.12 inch.

From the above description it will be seen that there has been provided a drain seal of simple and low-cost construction which does not require the use of a material such as a cellular sponge mass to prevent the flow of air and moisture between the fresh food compartment and the area of the cabinet adjacent the exterior surfaces of the freezer liner 2.

While there has been shown and described a specific embodiment of the invention it will be understood that it is not limited thereto and it is intended by the appended claims to cover all such modifications as fall within the true spirit and scope of the invention,

What is claimed is:

l. A refrigerator comprising:

a metal liner defining an upper freezing compartment and having refrigerant tubing engaging the outer surface thereof;

a lower fresh food compartment having a top wall spaced from said freezing compartment;

a water-collecting receptacle composed of molded foamed-resin, moisture-impervious, heat-insulating material and being positioned between said compartments and generally spaced from said freezer compartment for receiving, during defrost of said freezer compartment, defrost water formed by the melting of frost collecting on the outer surfaces of said freezer compartment during normal refrigerating operation;

a unitary drain means for draining defrost water from said receptacle into said fresh food compartment;

said drain means being composed of plastic material and comprising a disc-shaped upper portion having a peripheral edge molded into said foamed-resin receptacle and a plurality of perforations in the central portion thereof;

said drain means including a tubular bottom portion extending from the perforated central portion into said fresh food compartment;

the perforated central portion being cooled by said refrigerant tubing to below-freezing temperatures during normal refrigeration operation of said refrigerator so that frost forms in and seals the perforations to block air flow through said drain means during normal refrigerating operations of said refrigerator.

2. A refrigerator according to claim 1 in which said receptacle is composed of foamed polystyrene and said drain means of unformed polystyrene resin. 9

UNITED STATES PATENT OFFICE CERTIQFICATE OF CORRECTION Patent No. 3,774,408 Dated November 27, 1973 Inventor(s) Leslie L. Pruehs It is certified that error appears in the above-identified patent I and that said Letters Patent are hereby corrected as shown below:

\ Claim 2, Lihe 55, "unformed" should be "unfoamed" Claim 2, Line 55, after "resin' delete "9" Signed and sealed this 16th day of July 1974.

(SEAL) Attest:

McCOY M. GIBSON, JR. C. MARSHALL DANN Commissioner of; Patents Attesting Officer USCOMM-DC 60876-P69 FdRM PO-1050 (10-69) I U.5. GOVERNMENT PRINTING OFFICE I969 O3S6-334 

1. A refrigerator comprising: a metal liner defining an upper freezing compartment and having refrigerant tubing engaging the outer surface thereof; a lower fresh food compartment having a top wall spaced from said freezing compartment; a water-collecting receptacle composed of molded foamed-resin, moisture-impervious, heat-insulating material and being positioned between said compartments and generally spaced from said freezer compartment for receiving, during defrost of said freezer compartment, defrost water formed by the melting of frost collecting on the outer surfaces of said freezer compartment during normal refrigerating operation; a unitary drain means for draining defrost water from said receptacle into said fresh food compartment; said drain means being composed of plastic material and comprising a disc-shaped upper portion having a peripheral edge molded into said foamed-resin receptacle and a plurality of perforations in the central portion thereof; said drain means including a tubular bottom portion extending from the perforated central portion into said fresh food compartment; the perforated central portion being cooled by said refrigerant tubing to below-freezing temperatures during normal refrigeration operation of said refrigerator so that frost forms in and seals the perforations to block air flow through said drain means during normal refrigerating operations of said refrigerator.
 2. A refrigerator according to claim 1 in which said receptacle is composed of foamed polystyrene and said drain means of unformed polystyrene resin. 9 